Areas along the Great Lakes are bracing for big lake effect snows this weekend -- and there probably will be more this winter.
The reason: Water temperatures on all five lakes are higher than normal, so little ice has formed.
When a frigid wind sweeps over all that open water, it can create the huge cloud walls capable of dumping several feet of snow.
An analysis from the NOAA Great Lakes Environmental Research Lab shows only 6 percent of the Great Lakes covered in ice. The pockets of ice are on small bays or narrow channels, like Green Bay, Wisc., or the Makinac Straits in northern Michigan.
Shallow Lake Erie is almost completely ice-free. So is Lake Superior, the northern-most lake.
That's very different from 2014 and 2015, when water temperatures were much lower. The maximum ice cover stretched across almost all of the lakes' surface, as this NOAA animation of ice cover from 1973-2016 shows.
At this point in 2015, 34 percent of the Great Lakes was covered in ice. At this time last year, 10 percent was covered, according to NOAA statistics.
This year is shaping up to be more like 2012 or 2002, when the lakes had little ice.
This weekend, areas to the east of Lake Erie and Lake Ontario are under lake effect snow warnings.
And over the rest of winter, if the Great Lakes remain ice-free, other parts of the region could also be hit with big snows.
So watch out.